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<head>
    <meta charset="UTF-8">
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    <title>Document</title>
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<body>
    <script>
        let [x = 1] = [undefined];
        x // 1

        let [x = 1] = [null];
        x // null
        
        //上面代码中，如果一个数组成员是null，默认值就不会生效，因为null不严格等于undefined。
        

    </script>
</body>

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